Anastomosis procedures are required for connecting or re-connecting certain body tissues, such as in performing part of a surgical procedure. In particular, anastomosis procedures are used for joining one hollow vessel or structure to another hollow vessel or structure so that the interior portions of the vessel can fluidly communicate with each other. In one type of procedure, which may be referred to as an end-to-end anastomosis, severed tissues of a first vessel are coupled, usually by suturing or stapling, to severed tissues of a second vessel. The tissues may be part of a body lumen such as a blood vessel, intestinal or other digestive system tissue, or tissues relating to the urinary system. As one example, in a radical prostatectomy, a surgeon removes all or most of a patient's prostate. Because the urethra travels through the prostate immediately before reaching the bladder, the upper part of the urethra is also removed with the surgery. The procedure leaves a severed urethral stump and a severed bladder neck. To restore proper urinary functions, the bladder and the urethra must be reconnected, which can be a relatively difficult and complex procedure. These difficulties can occur as a result of the tendency of the urethral stump to retract into adjacent tissue after being severed and also due to the fact that the urethral stump is obscured by the pubic bone. These and other factors can make the area difficult to access by the surgeon, particularly for extending periods of time when performing the surgical procedure.
Conventionally, a surgeon may execute delicate suturing operations with tiny, fine needles to reconnect these or other anatomical bodies. However, installation of sutures with a needle to connect severed tissues can be a difficult and technique-sensitive task. Many factors can make the task difficult, including a very small amount of tissue to work with (e.g., at the urethral stump and at the bladder neck), and proximal sensitive tissues such as ureters at a bladder and a proximal nerve bundle and sphincter at a urethral stump. These factors result in complicated and delicate suturing procedures that, if not performed properly, could result in complications such as leakage, difficulty in healing or failure to heal, or specific conditions such as incontinence or impotence.
To reduce the risks involved in conventional suturing procedures, anastomosis devices have been developed that include a drainage feature and tissue approximating structures that allow for reconnection of tissues without using traditional sutures. These anastomosis devices advantageously use tissue approximating structures to reconnect severed tissues during anastomosis procedures, which can both reduce the risks during the surgical procedure and also provide a significant reduction in the amount of time required to perform certain anastomosis procedures. The tissue approximating structures can be activated by a number of different actuation mechanisms that the surgeon can use to extend and retract the tissue approximating structures relative to adjacent tissue structures, as desired. There is a need, however, to provide a variety of actuation mechanisms for anastomosis devices in different surgical situations, and also a desire to provide additional safety features and removal features for anastomosis devices.